<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        function sum(num1,num2) {
            this.sum1 = num1 + num2;
        }
        sum(10,20);
        console.log(window.sum1);
        (function a(){
            
            this.a = 1;
        })();
        console.log(a);
        
        var obj = {
            name:'jack'
        }
        
        sum.apply(obj,[30,80]);
        console.log(obj);
         var arr=[];
         arr.push.apply(arr,[10,100,30,33]);
         console.log(arr);
         
    </script>
</body>
</html>